Christopher Nolan makes layered and intelligent films, the sort that hide myriad secrets and take multiple viewings to properly crack. Seven years after its release, The Dark Knight probably remains the film-maker's most popular movie, and thanks to the scholars at Clickhole, you can now uncover a wealth of new detail pertaining to the feature in their video essay. Check it out below via Yahoo. Chris Nolan really is an unorthodox director isn't he? Bravo to the folks at Clickhole for studying the film so intently, and dredging up minute details that even hardened fans weren't aware of. My personal favourite is Michael Caine's disappointment at the lack of a live marlin, but the essay's theory about the identities of Batman, Joker, Alfred and Two-Face also provide a lot of food for thought. (On a serious note, this is stellar send-up of fan theories and the obsessive way we sometimes over-analyse event films!) Are you surprised by these revelations? Do you have more to share? Let us know in the comments section below!